In the late 1980's, the cost of transporting commodities by rail in the United States was approximately three cents per revenue-ton mile, plus about one dollar per ton as fixed cost. The comparable cost of transportation by motor truck on public highways was approximately eight cents per revenue-ton mile, also plus an additional one dollar per ton as fixed cost.
The carrier's cost is primarily composed of two major direct costs and two major indirect costs. The largest direct cost is labor for the train crew or for the truck driver. In this instance, railroads enjoy about a 50 to 1 advantage over trucks. Trains are capable of enabling five men to transport 10,000 tons of material. On the other hand, a single truck driver can transport only about 25 tons. This is approximately an 80 to 1 benefit relative to labor costs. The second major direct cost is fuel, in which case the railroads can produce three to five times as many revenue-ton miles per gallon or per dollar of fuel as the trucks can produce.
One of the major indirect costs is the investment in the rolling stock. A 10,000 ton load requires at least five locomotives (costing one million dollars each) plus 100 freight cars at approximately forty thousand dollars apiece. This investment amounts to approximately one thousand dollars per ton of capacity. On the other hand, a new truck and trailer for hauling bulk commodities might cost in the range of one hundred thousand dollars for a 25 ton capacity, or about four thousand dollars per ton of capacity. Once again, the railroads show about a 4 to 1 advantage over trucks in this area.
The other major indirect cost is the upkeep of the roadway. American railroads spend approximately one-half cent per revenue-ton mile for maintenance of way and structures. Trucks running on public roads pay fuel, taxes and registration and use taxes which add up to roughly the same amount.
Based on the foregoing examples, railroads show approximately a 4 to 1 advantage in the cost of rolling equipment a 4 to 1 advantage in fuel and a 80 to 1 advantage in operator wages. Based on these numbers, it would seem that railroads should be able to completely dominate the transportation of bulk commodities.
In practice, however, railroads are most suited for hauling very large quantities (e.g. 10,000 tons in a unit train of coal). Whereas, sand, gravel, stone, and other bulk commodities seldom travel in such large quantities to make up a complete maximum train. This means that many shipments must be delayed while waiting for the railroads to assemble less than trainload lots into an economical train. After the material arrives at the destination, it still must be unloaded from the railroad cars and carried to the point of use. In many cases, this involves truck transportation, and in all cases it involves the unloading of railroad cars.
Many systems have been devised for fast unloading of railroad cars. Most of these require expensive facilities costing millions of dollars. Such systems serve to turn the cars upside down or allow the material to be dropped through the track onto conveyer systems. Unfortunately, a large portion of the sand, gravel, and stone moved by railroads travels in open topped gondola cars which must be unloaded by hand or by some type of machinery. Usually, such machinery dips out one bucket at a time and places it on the ground or onto waiting trucks. This is a fairly slow process which also requires a large number of cars to wait while a single machine unloads them at a time.
Various United States patents have shown rather cumbersome methods for unloading such gondola cars. U.S. Pat. No. 4,099,635, issued on July 11, 1987, to Leonard et al, shows a loader that moves along the top edges of adjacent gondola cars. A shovel then dips into the gondola cars for loading and unloading. U.S. Pat. No. 4,723,886, issued on Feb. 9, 1988, to L. E. Ferderking, shows an apparatus for loading and unloading gondola cars. This device also utilizes tracks that extend along the top edge of the gondola car so that a hydraulic excavator may dip into the gondola car so as to extract material. These prior art patents show devices that are quite cumbersome and difficult to use. Since a great deal of leverage is required for the operation of these types of tractor/shovel systems, complicated attaching mechanisms, external lines, and other devices are required so as to maintain the apparatus in proper position, and with proper leverage, along the top edges of the railroad car.
Because most railroad shipments are less than a unit train load, their arrival cannot be predicted with any degree of certainty. As a result, loaded cars must frequently wait several days to be unloaded. Because of these and other problems, the average United States railcar makes only about one revenue trip per month, whereas the average truck makes several revenue trips per week, and on short hauls may even make five or six revenue trips per day.
As a result, one of the major indirect advantages of rail transportation is totally eliminated and reversed. That is, rather than having a 4 to 1 advantage in the investment of rolling stock per ton of capacity, under present methods, the railroads suffer at least a 4 to 1 disadvantage in this factor.
The present invention serves to eliminate the major disadvantage of rail transportation by allowing small shipments to be unloaded immediately upon arrival. This enables the whole assembly of locomotive and cars to make a revenue trip every day or even more on very short hauls.
The use of gondola cars having a continuous trough extending throughout the cars would be one solution to the problem. Such a continuous load-carrying car would enable a vehicle to traverse the interior of the train while unloading. Unfortunately, the only continuous gondola car configuration is not designed to be unloaded by a vehicle traversing the floor.
U.S. Pat. No. 4,754,710, issued on July 5, 1988, to K. C. Kieres describes a railway car for carrying freight. In particular, this patent describes the use of a continuous railway car having one continuous trough. The trough is supported at each end wall by trucks. The sidewalls are made up of a plurality of side panels. The side panels have overlapping systems to permit relative motion between adjacent panels for maneuvering curves and hills. The floor has a plurality of laterally and longitudinally extending slope sheets. A flexible center sill extends continuously for the entire length of the railway car.
It is an object of the present invention to provide a system for the unloading of gondola cars and allow such cars to be unloaded at a remote location.
It is another object of the present invention to provide a system that enables conventional tractor/shovel configurations to be utilized for the unloading of gondola cars.
It is still a further object of the present invention to provide a gondola car configuration that allows such gondola cars to be utilized around the sharpest of turns.
It is still a further object of the present invention to provide an unloading system that enables the tractor/shovel to gain sufficient leverage for effective material unloading.
It is another object of the present invention to provide an unloading system that maximizes economies and capacities while minimizing expense, complexity, and capital and labor investment.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.